-LRB- CNN -RRB- -- `` The Big Bang Theory '' is back in action .

The top-rated comedy returns to CBS on Monday with its eighth season premiere after contract talks briefly held up production in late July .

` Big Bang Theory ' contract talks stall production

But since the contracts have been hammered out -- with some of the leading cast members now earning a reported $ 1 million per episode -- `` The Big Bang Theory '' is moving forward with what sounds like a season full of changes . Let 's hope Sheldon can cope this time around .

Here 's what we 've heard fans should expect for season 8 of `` The Big Bang Theory '' :

Sheldon 's return

At the end of season 7 , Sheldon Cooper -LRB- Jim Parsons -RRB- announced that he could n't handle all of the new developments happening in his life , and was `` getting on a train and leaving forever . ''

His plan to `` live off the land '' did n't go so well , as he makes his return in season 8 's hour-long premiere after getting robbed on the train . As a sneak peek shows , Leonard -LRB- Johnny Galecki -RRB- and Amy -LRB- Mayim Bialik -RRB- have to head down to Arizona to collect Sheldon and bring him back home .

Do n't expect a wedding for Leonard and Penny

Penny -LRB- Kaley Cuoco-Sweeting -RRB- and Leonard may have ended the seventh season with an engagement , but executive producer Steve Molaro told TV Guide they 're not rushing the couple to the altar . They 're going to take it so slowly that Molaro is `` 99 % '' sure that a wedding wo n't happen in season 8 .

`` We 're not anti-wedding . It 's just they 're feeling this out , '' the EP said . `` Stuff with money and things like that can come up with them being engaged without us having to rush to the altar and change the fabric of the show . ''

Besides , Molaro added , he 's just not ready to see Leonard and Sheldon cease being roommates .

Sheldon and Penny get new jobs

Not to mention that Penny has a big career shift in front of her : The waitress/actress is leaving the drama behind for a new job as a pharmaceutical sales rep at Bernadette 's -LRB- Melissa Rauch -RRB- company . You 'll see her interview with her new , much shorter haircut during tonight 's two-part premiere .

The new gig has the potential to rock the boat in Penny 's new engagement . `` It alters their dynamic because now she 's actually doing well financially , '' Molaro told TVLine . `` It 's a new chapter for her . ''

Along with Penny , Sheldon 's also carving a new path at work . He 'll get to study dark matter as long as he takes a job as a junior professor . Yet it looks like no one 's interested in taking Sheldon 's course -- except for Howard , that is .

Howard has mother issues

Perhaps Howard -LRB- Simon Helberg -RRB- just really needs the distraction , since he 's butting heads with his mother 's caretaker , Stuart .

`` He 's playing too many roles for my character to feel comfortable with , '' Simon Helberg , who plays Howard , says of the new season . `` It 's a bit of a threat to Howard that he 's being replaced as a son . ''

Sheldon and Amy are taking it slow

Amy was not pleased that Leonard and Penny let Sheldon go off on his soul-searching journey , and the couple 's reunion is n't exactly romantic . It 's Leonard that Sheldon calls when he gets into trouble , and when Amy shows up with Leonard at the police station , a surprised Sheldon asks , `` Why did you come ? ''

But the couple 's come too far for Sheldon 's social fumbles to get in their way . `` We 're always moving them forward in baby steps , '' producer Molaro told TVLine . '' `` They 're on the same trajectory that they 've been on since they met , and that is she is continuing to drag him along into this relationship , whether he wants to admit that he likes it or or not . He 's come a long way . ''

Emily and Raj are going strong

Season 7 ended with each main character finding love , and that included Raj -LRB- Kunal Nayyar -RRB- , who 's now dating Laura Spencer 's Emily .

The couple is still together as season 8 begins , and Molaro promises that we 'll learn more about Emily as the season progresses .

`` The Big Bang Theory '' will air on CBS Monday nights at 8 p.m. ET until October 30 , when it will shift back to its usual timeslot of Thursdays at 8 p.m. ET .

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The eighth season of `` The Big Bang Theory '' premieres Monday at 8 p.m.

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The premiere will feature two new episodes

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The series will shift back to Thursdays starting October 30